Leading exponential finite size corrections for non-diagonal form factors

Zoltán Bajnok, Márton Lájer, Bálint Szépfalvi, István Vona

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We derive the leading exponential finite volume corrections in two dimensional integrable models for non-diagonal form factors in diagonally scattering theories. These formulas are expressed in terms of the infinite volume form factors and scattering matrices. If the particles are bound states then the leading exponential finite-size corrections (μ-terms) are related to virtual processes in which the particles disintegrate into their constituents. For non-bound state particles the leading exponential finite-size corrections (F-terms) come from virtual particles traveling around the finite world. In these F-terms a specifically regulated infinite volume form factor is integrated for the momenta of the virtual particles. The F-term is also present for bound states and the μ-term can be obtained by taking an appropriate residue of the F-term integral. We check our results numerically in the Lee-Yang and sinh-Gordon models based on newly developed Hamiltonian truncations.

Original languageEnglish
Article number173
JournalJournal of High Energy Physics
Issue number7
Publication statusPublished - Jul 1 2019



  • Field Theories in Lower Dimensions
  • Integrable Field Theories
  • Nonperturbative Effects

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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